The present invention relates generally to a field assembly for a motor and more particularly to an integral flexible insulator for use in this type of field assembly.
As is well known in the art, a motor includes a series of field assemblies which cooperate in the rotation of the rotor. Each field assembly is rigidly attached to the motor frame which is usually cylindrical. The rotor is centrally located and driven about an axis substantially colinear with the axis of the motor frame.
Each field assembly includes a winding and pole piece or member. The winding substantially encompasses the pole piece so as to effectively produce flux therein.
In the past, field assemblies have been manufactured using a slow, labor-intensive process. The winding, usually machine-wound cooper wire, is wrapped with glass tape, in a half lap fashion, so as to insulate the winding from the pole piece and motor frame. Generally tape thickness is in the range of 0.005 to 0.015 inch.
The taped winding is then dipped in a varnish bath. Under wick action, the varnish passes through the glass tape in the hope that it will coat and bond together the wire forming the winding.
The winding is then fitted upon the pole piece and both are secured within the motor frame. In the assembled state, the winding is "pinched" or compressed between the pole piece and motor frame.
The pole piece is composed of metal laminations. The exterior surfaces thereof must be smooth to avoid snagging and tearing of the glass tape during the manufacturing process.
In other instances, insulating sheets such as nylon, mylar or laminations thereof, are inserted between the motor frame and field assembly during manufacture. These sheets further isolate the winding from motor frame.
The entire motor is then painted. This provides a protective coating.